Electrical apparatus



1 270 Q 9 c. P. WHITE ELECTRICAL APPARATUS Filed Nov. 6, 1923 ji'eamr jmwgm MA;

1,618,499 FFICE.

I. ,0! LYNN, MASSACHUSETTS.

I, I nuance. I Application fled Rovember '8, 1988. Serial Io. 678,045.

The present invention relates'to electrical apparatus and more particularly to apparatus for controlling electrical conduction in a circuit by the emission and control of electrons.

The usual form of apparatus for control of electrical conduction (for' example, in

amplification or rectification of radio or telephone signals) is the threeelement the-r-' mionic vacuum tube consisting of a heated filament, a id and a plate, the electron flow from t e filament to the plate being controlled by the potential of the grid.. The

elements must be enclosedv in an evacuated receptacle, because the use of the device in the atmos here would not onlycause the ordinary ament to be consumed, but would also vitiate the operation of the tube through ionization efiects. Notwithstanding the importance of the vacuum tube in the art, it may safely besaid that it is open to the serious disadvantages of being expensive, delicate and liable to breakage, and difiicult to repair. Moreover, the power capacity of the tube is limited by the fact that the mounting of the elements within the receptacle is a matter of considerable difliculty, increasin with the size of the elements.

. Theob ect of the present invention is to provide a-convenient and inexpensive apparatus which may be used in place of a thermionic vacuum tube in any of the usual circuits, which may be made of substantially any desired power capacity, and which may be readily repaired in case of injury to any of its parts.

Accordin to the invention, there is provided a p urality of electrodes, each of which performs the functions of a corresponding element in a vacuum tube, together with layers of dielectric which is permeable to electrons interposed between the electrodes. I- have discovered that the flow of electrons is not substantially impeded by the presence of the dielectric. No evacuation is necessary, the dielectric completely filling the spaces between the electrodes to prevent any ionization effects, and also covering and protecting the electrodes.

Other features of the invention consist of certain novel features of construction, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be apparent to those skilled in the art from the following description.

In theaccompanying drawings Figure 1 1s an elevation partly in section of the referred embodiment of the invention; ig.

'2 is adiagram of a simple circuitiembodying the apparatus shown in Fig. 1; and Fig. 3 is a modification .of the invention.

The illustrated embodiment of the invention comprises a plurality of concentrically arranged electrodes, 4, 6, 8 and 10, separated by layers of a dielectric which is permeable to electrons. The electrode 4 is an imperforate anode. The electrode 6 is in the form of a perforated plate or screen, and constitutes the electron controlling element to alter the paths of electrons. given off by the electron emitting element 8. Theelement 8 may be of any desired form but conveniently consists of a filament wound in ooves in the dielectric layer. The material of the filament is such as.to give off electrons profusely when heated and preferably consists of an oxide coated wire of the. type Well known to those, skilled in the art. Surrounding the filament is the heater 10 which consists of a heating coil of the usual form, adapted to be connected across a power supply, and which may also be constructed'to emit electrons if desired. In certain cases it is desirable to make a single electrical connection between the elements 8 and 10, as willhereinafter-more fully appear. The di electric support consists of a central core of dielectric material 12, preferably porcelain, which is surrounded by the anode 4. Porcelain cylinders 14, 16 and 18 are interposed between the remaining elements, as illustrated in the drawings and an 'external cylinder 20 encloses the entire assembly. Porcelain end disks 22 are provided which are held in position upon the ends of the cylindrical assembly by means of a stand 24 at each end, consisting of a two-part annular band 26 having shoulders 28 and 30, the former engaging an annular recess in the cylinder 20 and the latter bearing against the outer edge of the end. disk. Terminals 32 are brought out to the end disks for the heater coil, terminals 34 for the filament, and single terminals 36 and 38 for the electron controlling element and the anode, respectivel'y. In the operation of the apparatus, the heating coil is connected across a suitable voltage. As the electron emitting element 8 is heated by the heating coil, it 'ves ofi electrons which are attracted towar the anode 4 by a positive potential, the flow of electrons from the filament to the anode being controlled by the element 6 upon which suitable potentials may be impressed for amplification or rectification. The flow of electrons takes place through the porcelain.

Inasmuch as the control of electron flow by means of an element between the electron emitting cathode and the anode is similar in princip e to the control in a vacuum tube, it will be seen that the above described apparatus may be used in any of the circuits in which the thermionic vacuum tube is now commonl used, one of the simple forms of circuits ein illustrated dia rammatically in Fig. 2. T 1e electron emitting element 8, the control element 6 and the anode 4 are illustrated according to the usual convention for showing the filament, grid and plate, respectively, of a vacuum tube. The heating coil 10 is connected by conductors 40 to an alternating or direct current supply of sufficient voltage to heat the element 8 to give off electrons. signed for amplifying impulses impressed on the tuned circuit 42, which is connected between the elements 6 and 8, the amplified currents appearing in the plate circuit 44, which is connected between the element 8 and the anode 4 and which is ener ized by a battery 46. A connection 48 is illustrated betweenthe centers of the filament and the heatin coil. This connection is o tional. If use it places the heating coil at t e same potential as the filament with respect to the anode 4 and thus renders any electrons given off by the heating coil available for being attracted directly by the positive otential on the anode. In such a case, the ament and heating coil constitute in effect one element. However, if the connection 48 is omitted, the filament alone constitutes substantially the only source of electrons for the apparatus. The heating coil also may give off electrons if heated to sufficient temperature, but only such electrons as arrive within the electric field betweenthe anode 4 and cathode 8 will be available for conduction. If the heating coil and the cathode are arranged very closely together, a considerable number, if not all, of the electrons will wander into the electric field. The disadvantage of the loss of electrons from the heating coil by the omission of the connection 48 is as a practical matter compensated for by the fact that the element 8 is heated with no potential gradient. It will be preciated that the emission of electrons and the distribution of the anode current when the connection 48 is used will be affected by the drop in otential all along the heating coil. It is elievcd, furthermore, that there is a condenser effect which exists between the heating coil or the filament and the other elements of the up paratus, this condenser effect being especially apparent when the connection 48 is The illustrated circuit is de-' omitted. The condenser cfi'ect exists from the fact that when a conductor gives oil an electron the conductor itself becomes positively charged, thus givin an adjacent conductor a negative charge by induction.

heating coil and the filament so that electrons are not drawn from the heating coil directly into the electric field, there is nevertheless an electrostatic inducbon efl'ect which places a charge on the filament from the electrons which are given off by the heating coil. Although this efiect is not perfectly understood, it is believed to contribute to the flow and control of electrons. In any event, the condenser effect is quite considerable because of the large opposing surfaces of the electrodes and the high dielectric constant of the porcelain.

The apparatus shown in Fi 3 consists in the addition of another set 0 elements outside of the heating coil. The internal ele ments 4, 6, 8 and 10 are retained as before but the apparatus is built up with an additional anode 54, control element 56 and electron emitting element 58, all surrounding the heatin coil 10, and the elements being separated by layers of porcelain and 72 as before. The two sets of elements are entirely separate and if desired may be used as two distinct devices. The corresponding elements of the inner and outer sets may be connected in series or in parallel, or the two sets may be connected so as to give two stages of amplification by using each one separately, as will be obvious. The heating coil thus works at practicall double the efficiency of the single set out t in that the same amount of heat will practically suffice for energizing both the inner and outer sets.

It will be appreciated that in addition to the electrical features peculiar to the present invention, the apparatus also possesses certain desirable mechanical qualities. The electrodes are at all times firmly supported and protected by the core so that they are not liable to-microphonic effects which occur in vacuum tubes from slight shocks varying the relative positions of the electrodes. The apparatus may be of any desired power capacity since the sup )orts may be extended to take care of electrodes of any desired magnitude. Furthermore, merely by loosening the annular clump members, the whole apparatus may be quickly and conveniently taken apart so that repairs of any broken or burned out elements may be readily made.

Although the pro fcrrcd combination and. arrangement of parts has been illustrated and described, it will be appreciated that the invention may be modified from this specific construction without departing from the broader features of the invention except as limited in scope by the appended claims.

If therefore, there is no connection between the For example, although it is preferred to cmploy concentric cylindrical electrodes Wit It the control elect-rode and cathode outside of the anode, nevertheless electrodes of any desired shape and arrangement may obviously be employed, it-being only necessary that the control element be arranged to influence the flow of electrons between the cathode and anode.

What I claim is:

1. An electrical apparatus comprising an electron emitting cathode, an anode,'a control electrode between the cathode and the anode, and layers of inert dielectric material permeable to electrons formm g the exclusive separating media between the electrodes.

2. An electrical apparatus comprismg a I electrons and forming the sole means for separating and supporting the electrodes.

In Witness whereof, I hereunto set my hand this first day of November, CHARLES P. WHITE. 

